1. Field of the Invention
This invention relates to apparatus for providing protection in electrical power distribution systems, and more particularly, to miniaturized two pole circuit breakers for providing protection for arc faults and ground faults, that are capable of being mounted in a single standard three-quarter inch or one-inch slot of a load center panel.
2. Background of the Information
There has been an increased interest in providing protection for arc faults as well as ground faults in load centers without the need for increasing the size of load center panels. Arc faults are intermittent high impedance faults which can be caused, for instance, by worn insulation, loose connections, broken conductors, and the like. Because of their intermittent and high impedance nature, they do not generate currents of sufficient instantaneous magnitude or sufficient average current to trigger the thermal-magnetic trip device which provides the short circuit and overcurrent protection. Various types of arc fault detectors have been proposed, but except for the circuit described in U.S. Pat. No. 5,889,643 issued Mar. 3, 1999, such detectors have not been adapted in miniaturized form so they can fit into common load center panels having three-quarter inch or one-inch slots. A further need exists for an arc fault breaker in a two pole design that can fit within a single slot within a load center panel.